Molecular phylogenetic relaionships of unicellular green algae, Chlorellales and its relaives.

小球藻目等33种单细胞绿色藻类的18 SrDNA序列分析（博尔德和韦恩，1978年）对12种小球藻进行了系统遗传学分析，其中衣原体目（Chlamydomonadales）3种，四孢菌目（Tetrasporales）2种，绿球藻目（Chlorococcales）6种，绿球藻目（Chlorococcales）8种，毛藻目（Chaetophorales）1种，盾毛藻目（Chaetopeltidales）1种。该目藻类分布于绿藻门和绿藻门。2）双鞭藻的基身顺时针方向分为Tetracystis-、Dunaliella-和Volvox-3个分支。四胞藻目的四分体形成者被包括在四胞藻分支中，与该目的类肌氨酸形成者分开。杜氏藻属和团藻属的差异可能是由于它们的裸藻和薄壁藻群造成的。3）通过对四鞭毛无壁绿色藻类的分析，得出细胞壁在不同的系统发育线中多次出现的结论，并提出了Oltomannsiellopsidales一新目。5gen.et）对拟绿球藻属中的一种海洋绿球藻，提出在石藻目中建立一个新属的建议。6）棕榈叶藻属（Palmophyllum）是四孢目中的一个种，其细胞周围有凝胶状基质，生活在海底岩石上，与Prasinophytes关系最密切。

18SrDNA sequece data of 33 species of unicellular green algae, indluding the Chlorellales (sensu Bold & Wynne 1978) (12 species), Chlamydomonadales (3), Tetrasporales (2), Chlorococcales (6), Chlorosarcinales (8), Chaetophorales (1) and Chaetopeltidales (1), were analyzed phylogenetically.1) The Chlorellales is polyphyletic, and the algae of this order distribute in the chlorophycean and trebouxiophycean clades. Number of species of the latter clade is more than the former.2) Biflagellate members whose basal body orientation is clockwise are divided in the Tetracystis-, Dunaliella-, and Volvox-clade. Tetrad formers of the Chlorosarcinales are included in the Tetracystis-clade, being separated from sarcinoid formers of the order. Difference between Dunaliella-clade and Volvox-clade may be caused by their naked and thin-walled swarmers respectively.3) From analysis of quadriflagellate wall-less green algae, it was concluded that the cell wall occurred several times in separate phylogenetic lines, and we proposed a new order Oltomannsiellopsidales.4) A marine chlorococcalean species of the genus Neochloris is obviously a ulotrichalean alga of the Ulvophyceae, and we proposed Pseudoneochloris marina gen.et sp.nov.5) For a marine chlorosarcinale an species of the genus Chlorosarcinopsis, we proposed to establish a new genus in the Ulotrichales, Ulvophyceae.6) Palmophyllum, a species of the Tetrasporales with gelatinous matrix around cells living on rocks in bottom of sea water, is demonstrated to be most related with Prasinophytes.